#include <stdlib.h>
#include <math.h>
#include <stdio.h>

struct Vertex {
  double x;
  double y;
};

struct Vertex* newVertex(double x,double y){
  struct Vertex* this 
    = (struct Vertex*)malloc(sizeof(struct Vertex));
  this->x=x;
  this->y=y;
  return this;
}

double betrag(struct Vertex* this){
    return sqrt(this->x*this->x+this->y*this->y);
}

int main(){
  struct Vertex* v1 = newVertex(17,4);
  printf("%f\n",betrag(v1));
  return 0;
}